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What does "what" refer to here?

 
 
Reply Sat 2 Jan, 2016 12:36 am
Does " but depend on what is being measured" mean " but depend on what is being measured (by the measurer(s)/people who do measuring)"?
If so, "what" should be referred to "the target/the part of universe that gets measured"?


Context:

In cosmology, in other words, one shouldn't follow the history of the universe from the bottom up because that assumes there's a single history, with a well-defined starting point and evolution. Instead, one should trace the histories from the top down, backward from the present time. Some histories will be more probable than others, and the sum will normally be dominated by a single history that starts with the creation of the universe and culminates in the state under consideration. But there will be different histories for different possible states of the universe at the present time. This leads to a radically different view of cosmology, and the relation between cause and effect. The histories that contribute to the Feynman sum don't have an independent existence, but depend on what is being measured. We create history by our observation, rather than history creating us.

-Stephen Hawking
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View best answer, chosen by oristarA
dalehileman
 
  1  
Reply Sat 2 Jan, 2016 12:22 pm
@oristarA,
Forgive me Ori but

http://onelook.com/?w=Feynman+sum&ls=a

Might it have something to do with the interaction of protons and electrons

http://onelook.com/?w=feynman&ls=a&loc=home_ac_Feynman

0 Replies
 
Tes yeux noirs
 
  1  
Reply Sat 2 Jan, 2016 12:38 pm
oristar, your question is not clear. Are you asking about grammar, or cosmology?
oristarA
 
  1  
Reply Sat 2 Jan, 2016 01:34 pm
@Tes yeux noirs,
Tes yeux noirs wrote:

oristar, your question is not clear. Are you asking about grammar, or cosmology?



Grammar.
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dalehileman
 
  1  
Reply Sat 2 Jan, 2016 02:08 pm
@Tes yeux noirs,
Quote:
grammar, or cosmology?
Dunno Tes, it sounds very technical

https://www.quora.com/What-is-Richard-Feynmans-sum-over-paths-approach-to-quantum-mechanics
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Tes yeux noirs
  Selected Answer
 
  2  
Reply Sat 2 Jan, 2016 03:01 pm
Quote:
Does " but depend on what is being measured" mean " but depend on what is being measured (by the measurer(s)/people who do measuring)"?


Yes, obviously. "What is being seen", of course means "what is being seen by the people who are doing the seeing".

Quote:
If so, "what" should be referred to "the target/the part of universe that gets measured"?


Yes, of course.

oristarA
 
  1  
Reply Sat 2 Jan, 2016 07:16 pm
@Tes yeux noirs,
Tes yeux noirs wrote:

Quote:
Does " but depend on what is being measured" mean " but depend on what is being measured (by the measurer(s)/people who do measuring)"?


Yes, obviously. "What is being seen", of course means "what is being seen by the people who are doing the seeing".

Quote:
If so, "what" should be referred to "the target/the part of universe that gets measured"?


Yes, of course.



Excellent.
Now we have had the foundation to move forward to see the logic of the conclusion made by the author:

Quote:
The histories that contribute to the Feynman sum don't have an independent existence, but depend on what is being measured. We create history by our observation, rather than history creating us.


It seems better to have written as " The histories that contribute to the Feynman sum don't have an independent existence, but depend on the observation made by the people who are doing the measurement. We create history by our observation, rather than history creating us."

That is, we create history by our observation because our measurement has an impact on what is being measured.

To see this clearer, we have to confirm that "The histories" the author's talking about are the histories of the universe. Since we are very part of the universe, so the histories can not have an independent existence without us included. Our observation-the observation of "the very part of the universe"-will affect the rest of the universe. Thus we create history by our observation, rather than history creating us.

What do you think?
Tes yeux noirs
 
  1  
Reply Sun 3 Jan, 2016 05:07 am
@oristarA,
Quote:
To see this clearer, we have to confirm that "The histories" the author's talking about are the histories of the universe. Since we are very part of the universe, so the histories can not have an independent existence without us included. Our observation-the observation of "the very part of the universe"-will affect the rest of the universe. Thus we create history by our observation, rather than history creating us.

This is exactly what Feynman is saying.

oristarA
 
  1  
Reply Sun 3 Jan, 2016 05:18 am
@Tes yeux noirs,
Tes yeux noirs wrote:

Quote:
To see this clearer, we have to confirm that "The histories" the author's talking about are the histories of the universe. Since we are very part of the universe, so the histories can not have an independent existence without us included. Our observation-the observation of "the very part of the universe"-will affect the rest of the universe. Thus we create history by our observation, rather than history creating us.

This is exactly what Feynman is saying.




Thanks.
So you've agreed that "but depend on what is being measured" should edited into"but depend on the observation made by the people who are doing the measurement"?

Quote:
Quote:
The histories that contribute to the Feynman sum don't have an independent existence, but depend on what is being measured. We create history by our observation, rather than history creating us.


It seems better to have written as " The histories that contribute to the Feynman sum don't have an independent existence, but depend on the observation made by the people who are doing the measurement. We create history by our observation, rather than history creating us."
0 Replies
 
Tes yeux noirs
 
  1  
Reply Sun 3 Jan, 2016 05:32 am
I don't think the original needs editing; it is perfectly clear.
oristarA
 
  1  
Reply Sun 3 Jan, 2016 06:00 am
@Tes yeux noirs,
Tes yeux noirs wrote:

I don't think the original needs editing; it is perfectly clear.



a universe = (the observer/the measurer) + (the rest of the universe)

Before Feynman's era, people were unaware of that they themselves are the part of the universe and thought (the rest of the universe) has an independent existence. That is, their formula is:
a universe = the rest of the universe (or " the universe without them")
We know:
The rest of the universe = (what is being measured) (the observer/the measurer measures what is being measured)

So, the author should have said "but depends on the observer/the measurer", not "but depends on the rest of the universe/what is being measured".

Now, what is your opinion?
0 Replies
 
 

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